1. Field of the Invention
The invention generally relates to an article. More specifically, the invention relates to a frictional weld joint for an article, which comprises a thermoplastic material.
2. Description of the Related Art
The use of frictional weld joints for coupling together first and second body portions of an article is known in the art. A typically frictional weld joint comprises a first bead extending from the first body portion and a second bead extending from the second body portion. Each of the first and second beads of the typically frictional weld joint has a contact surface. The contact surfaces of the first and second beads are placed into contact with each other and a force is applied to the first body portion to generate friction at the contact surface of the first and second beads. The first and second beads are made from a thermoplastic material and the friction results in an increased temperature of the thermoplastic material. As a result of the increased temperature of the thermoplastic material, the first and second beads nest with one another. Subsequently, the force is removed from the first body portion for allowing the thermoplastic material to cool, which results in the first and second beads fusing together.
However, as the force is being applied, small amounts of the thermoplastic material break off from the first and second beads as flash. Small amounts of flash may be beneficial as a way of clearing the contact surfaces of dirt and sediment that might interfere with the fusing of the first and second beads. However, large amounts of flash result in waste and therefore increase manufacturing cost. Additionally, large amounts of flash can also interfere with the frictional weld joint thereby decreasing a strength of the frictional weld joint. Additionally, the flash generated may become loose during the intended life of the article resulting in failure of the frictional weld joint and possibly other components. For example, in the case of air intake manifolds, the flash may become loose and can mix with an air-fuel mixture and eventually get into the engine system, which is undesirable. Furthermore, the generation of flash is an indication of heat losses during the nesting of the first and second beads, which can potentially have a negative impact on a desired total penetration to be achieved by the first and second beads and therefore should be minimized as a good manufacturing practice. Therefore, there remains a need to provide an improved frictional weld joint.